Mentions:
Previously, we described specific characteristics of WSS that induce hematopoietic progenitor activity in two-dimensional adherent cultures of dissociated AGM (Adamo et al., 2009). In the present study, we hypothesized that WSS may play a role in specification of HSCs that support life-long adult hematopoiesis and so examined developmental time points that precede definitive HSC emergence in cells derived from the anlage of the AGM known as the PSp at embryonic day (E) 9.5 and from the AGM at E10.5. Runx1 and Myb, two master regulators of hematopoiesis, are transcriptionally up-regulated by shear stress typical of embryonic murine blood flow (5 dyn/cm2), as are other genes required for definitive hematopoiesis and lymphopoiesis, including Bcl11a, Etv6, Gata2, Gata3, Tcf, Rag1, and Rag2 (Fig. 1 A). Analysis of cell surface phenotype after WSS confirmed increases in two markers of hemogenic endothelium, CD144/VE-Cadherin and c-kit, in the live (DAPI−) population (Fig. 1 B). We observed a 5.2 ± 1.2–fold increase in the percentage of CD144+ ckit+ cells, a surface phenotype thought to distinguish a subset of endothelial cells with definitive HSC potential (Fig. 1 C; Eilken et al., 2009; Swiers et al., 2013).

Mentions:
Previously, we described specific characteristics of WSS that induce hematopoietic progenitor activity in two-dimensional adherent cultures of dissociated AGM (Adamo et al., 2009). In the present study, we hypothesized that WSS may play a role in specification of HSCs that support life-long adult hematopoiesis and so examined developmental time points that precede definitive HSC emergence in cells derived from the anlage of the AGM known as the PSp at embryonic day (E) 9.5 and from the AGM at E10.5. Runx1 and Myb, two master regulators of hematopoiesis, are transcriptionally up-regulated by shear stress typical of embryonic murine blood flow (5 dyn/cm2), as are other genes required for definitive hematopoiesis and lymphopoiesis, including Bcl11a, Etv6, Gata2, Gata3, Tcf, Rag1, and Rag2 (Fig. 1 A). Analysis of cell surface phenotype after WSS confirmed increases in two markers of hemogenic endothelium, CD144/VE-Cadherin and c-kit, in the live (DAPI−) population (Fig. 1 B). We observed a 5.2 ± 1.2–fold increase in the percentage of CD144+ ckit+ cells, a surface phenotype thought to distinguish a subset of endothelial cells with definitive HSC potential (Fig. 1 C; Eilken et al., 2009; Swiers et al., 2013).